Over the last century, it has become desirable to be able to check vessels containing fluid, powder, solid and other compounds for evidence of tampering before the end user opens the vessel. This ensures a proof of quality and purity for the end user who can be assured that the product is delivered from the manufacturing supplier free of tampering by third parties.
It has become more evident that some samples, for example those used in forensic applications, need to be assured in more than one direction. Hence, there is a need to be able to supply an end user with a sealed vessel which has visibly not been tampered with by a third party en route to the end user, and for that end user to then be able to send the vessel onwards with a tamper-evident security feature that allows the recipient to see that tampering has been inhibited. The use of re-usable closures or seals obviously carries the risk that an interloper might remove the closure, tamper with the contents of the container, and reseal the container using the re-sealable closure without arousing the suspicions of the end user.
U.S. Pat. No. 5,720,402 discloses a container and a tamper-evident cap which fits the container in at least two closure positions. The tamper-evident cap has first and second bands, and the container has an annular slot for trapping the first band when the cap is in the first closure position and for trapping the second band when the cap is in the second closure position. The first band is retained in the annular slot when the cap is removed from the container, but must itself be removed before the annular slot can accommodate the second band. A pull tab is provided in the first band to allow its removal. The present applicant believes the discarded band may be problematic.